Hi,aa, here is some of my advice and I hope it can help you(By the way, it looks like we two choose the same prompts)
The first passage:
1. After reading the first sentence I thought a running race was about to begin......er, well then, since you've written in the following sentences that you are going to clear the weeds and trail, then why don't you delineate your actions and mentation during the process at the beginning of the paragraph? You can give us a sense of flashback and I believe it can intrigue readers.
2. The last sentence of second paragraph can not convince me that your experience is enriching. I think points are enough, but you need some more words to reinforce them.
The second one:
1. Sincerely, I think 456 words are far from adequate......My teacher told me that the essays of students he knew who earned full scholarship and entered top universities are about one and a half page measured in the paper of A4; that should be about 900 words to 1000 words. I wrote 982 words......
I don't know whether you are going to expand your essay largely or not, so please tell me how you would like to do and then I can give you the contingent advice in order to improve it in my best effort.
Harmon
HongqingZhao